B–O–B bridged BOPPY derivatives: synthesis, structures, and acid-catalyzed cis–trans isomeric interconversion

Abstract

A new class of BOPPY derivatives has been facilely synthesized by a two-step reaction of coupling 3,5-dimethylpyrrole-2-carbaldehyde with 2,3-dihydrazinoquinoxaline (QDH) followed by coordinating with BF3·OEt2. The reaction mainly produces a...

Recent Advances in Highly Fluorescent Hydrazine-Inserted Pyrrole-Based Diboron-Anchoring Fluorophores: Synthesis and Properties

“…Owing to the important advantages above, the asymmetrical bisboron-anchoring BOPPY chromophore quickly attracted some attention as advantageous photophysical properties above and promising frameworks for building blocks and functional materials. [47][48][49][50] For example, in 2022, Ono and coworkers 47 reported a new family of BOPPY dimers as flag-hinge chromophores starting from the pre-modified diformyl-2,2'bipyrroles, which manifest good multicolor and circularly polarized emission. Shen and coworkers 48 developed B-O-B bridged BOPPY dimers by reacting 3,5-dimethylpyrrole-2carbaldehyde with 2,3-dihydrazinoquinoxaline, and following boron complex.…”

Aromatic-Ring-Fused BOPPY Fluorophores: Synthesis, Spectral, Redox Properties, and Bioimaging Application

“…For example, Ono 45 reported a series of BOPPY dimers from diformyl-2,2′bipyrroles as flag-hinge chromophores exhibiting multicolor and circularly polarized luminescence. Shen 46 developed B− O−B bridged BOPPY dimers by coupling 3,5-dimethylpyrrole-2-carbaldehyde with 2,3-dihydrazinoquinoxaline and found that the two diastereomeric isomers under weak acid could undergo feasible cis−trans interconversion owing to the acidcatalyzed B−N bond cleavage. Stark 47 developed novel BOPPY-based fluorescent dopamine D2 and D3 receptor ligands, which demonstrate relatively large Stokes shifts and provide versatile possibility for amine coupling.…”

Asymmetric Core‐Expanded BOPYOs: Facile Synthesis and Optical Properties

“…Fluorophores BODIPY, BOPHY, BOPPY and boranil, etc., which contain NÀ BÀ N, OÀ BÀ O or NÀ BÀ O bridges have been widely investigated because of their outstanding photophysical properties such as tunable emission, high fluorescent quantum yields, and high stability. [1][2][3][4][5][6][7][8][9] Unlike conventional N,N and O,Obidentate organic boron complexes, N,O-bidentate boron complexes, which can be prepared by B-coordination using the ligands 2-(pyridin-2-yl)phenol and its analogues, have only been developed in recent years. The low-symmetry or asymmetric structure of these N,O-bidentate boron complexes gives them unique photophysical properties such as a relatively large Stokes shift, [10][11][12][13][14][15][16][17][18][19] strong emission in solution and/or solid, [14,16,17,[20][21][22][23][24][25][26][27][28][29] NIR absorption and emission, [20,30,31] and anion sensing.…”

“…[34] The second one, which was synthesized from ortho-hydroxylated substrates and pyrrole in one step (Scheme 1 (5)(6)), is applied as a probe for detecting H + and F À ions. [35] The last one was prepared by condensation, oxidation and coordination reactions from aldehydes and pyrrole (Scheme 1 (7)(8)(9)). [36] Thus, the development of diverse sevenmembered N,O-bidentate organic difluroboron complexes is still an area for researchers to explore.…”

“…Fluorophores BODIPY, BOPHY, BOPPY and boranil, etc., which contain N−B−N, O−B−O or N−B−O bridges have been widely investigated because of their outstanding photophysical properties such as tunable emission, high fluorescent quantum yields, and high stability [1–9] . Unlike conventional N,N and O,O‐bidentate organic boron complexes, N,O‐bidentate boron complexes, which can be prepared by B‐coordination using the ligands 2‐(pyridin‐2‐yl)phenol and its analogues, have only been developed in recent years.…”